Deviometer



May 20, 1941. J, LYMAN 2,242,253

' DEvIoMETER Filed Jan. 13, 1938 2 Sheets-Sheet I .22 i 151g 5 J e? IIIIIIIIIIIIIIIIIHIIIIII1l INVENTOR osEPH LY AN May zo, 1941.

J. I YMAN v DEVIOMETER` v 2 Sheets-Sheet 2 Filed Jan. 13. 1938 INVENOR oss Ymmv Patented May `20,1941

DEVIOMETER Joseph Lyman, Huntington, N. Y., assignor t., Sperryl Gyroscope Company, Inc., Brooklyn,

Nt Y., a corporation of New York A Application January 13, 193s, serial No. 184,783

9Claims.

This invention relates, generally, to instruturning movement of a craft, such as an air craft, from its normal or straight-awaycourse,

and the invention has reference, more particu- Y larly, to a novel deviometer employing a constrained gyroscope for indicating the amount of turn.

'I'he principal object of the present invention is to provide a novel instrument of the above character providing meansA for visually indieating turning movement and the amount thereof, whereby the operator ofthe craft -employing the instrument may readily and instinctively correct vthe course of the craft as though he were observing some xed object with relation to the turning movement of .the craft.

` ments for indicating the amount of deviation or Y Another object of the present invention lies in theprovision of a novel deviometer of the above character, wherein a constrained gyroscope is mounted upon a rotatable platform or table and arranged, upon precessyion due to azimuthal turning of the craft,.to actuate differential condenser means to cause operation of a follow-up,u

Fig. 3 is a view in front elevation of the instrument with its casing removed.

Fig. 4 is a wiring diagram of the circuits involved.

Sinilar characters of reference are used in all l of the above gures to indicate corresponding Referring now to the drawings, the gyroscope I is shown as comprising a rotor I journalled'for' rotation on a horizontal spinning axis by' means of pivots 2 carried by the ring or rotorbearing` frame 3. 'l'his-- ring, in turn, is journalled for oscillation about Aa second horizontalaxis by means of pivots 4, the pivots 4 being supported in pedestals i mounted upon the rotatable ltable or platform The `axis of pivots 4, about which the rotor bearing frame 3 turns; preferably extends horizontally `at right angles t spin axis 2, so that precession about this axis will be instantly produced by ,turning the craft in azimuth. The gyroscope is preferably air driven, and for this purpose th'e entire`apparatus or device is preferably enclosed within a casing 1 which is made air-tight and through whichair is drawn by creating differential pressure within and without the casing. For lexample, the

,Y is' obvious that positive instead of negative air frlctionless in operation so as to put no load on the gyroscope and hence enhancing the .sensitivity of the device, such condenser means being A included in tunable circuits that are inductively related to avsource of high frequency oscillations, the said circuits feedingv a thermionic rate circuit controlling the follow-up motor driving the rotatable gyroscope supporting table.

Otherobjects and advantagesfwill'become apparent from the specification, taken in connection with the accompanying drawings wherein ture of Fig, 1.

pressure may be used to drive the rotor, if desired. i

Air for operating the rotor I is conveyed-ther to`from without casing 1 by means of a conduit 9 leading to an upstanding hollow shaft I0 that is iournalled in a frame' II, upon which the platform 6 is rotatably mounted.. 'I'he frame II is shown providedwith a cylindrical upper portion I2 that Yis preferably of insulating material,

gearing le for turning the nouow shaft In with- Y infra'me II. The upper end ofshaft I0 is secured to the platform 6, whereby turning of this shaft,l due to operation of motor l1, causes turning of the platform B and the gyroscope.

.denser plate i1 overlaps equal portions of condenser plates I8 and Il.

In order to centralize the gyroscope, i. e., in order to turn the same to normal position as the airplane resumes a straight course after a turn, spring means may be employed. This means is shown as a coil spring i9 having one end attached to the brack.

et 2i extending upwardly from one of the pedestals l, and its other end attached to a pin 2| projecting upwardly from the center line of rotor bearing frame 2. A dash pot is shown, having its cylinder 22 attached to the platform 8 and its plunger 23 attached to the rotor bearing frame 3, for the purpose of damping the A 360 scale 2l is shown carried by theplatform 6 and is visible through a window 2i provided in the front wall 'of the instrument.

'I'he condenser plate is shown as grounded upon the rotor bearing frame I, which, in turn, is grounded upon the frame through pedestals I, table 6 and shaft Il. Frame il is connected by lead 25' to the cathodes of rectier tubes 28 and 26' arranged in push-pull. The condenser plates I8 and i8' are insulated from pedestal 5 by the insulating member 21. and are connected by suitable leads and brushes to slip rings 28 and 28', respectively, fixed upon the upper cylindrical portion i2 of the frame Il. 'I'hese slip rings, in turn. are connected to terminal posts 29, 29', to which' leads 30 and'll' are connected. As shown in Fig. 4, these leads 3l and 30' extend to the grids of tubes 26 and 26'. Condenser plate I1, together with condenser plate I2. constitutes part of a tunable circuit also including an induotance coil 3| and a condenser 32. Similarly, condenser plates i1 and `il' constitute part of a tunable circuit also including coil 3|' and condenser 32.

An oscillation generator 32 supplies high frequency current to these tunable circuits through use of coupling coils 3E and 35', the latter being coupled to coils 3| and 3|. The radio frequency signal produced by oscillator I3 and reaching the grid of tubes 2li and 26 may be sharply varied by the adjustment of the condenser yplate i'! with rpect to plates i8 and i8'. The plates vof tubes 2l and 2G ere supplied with commercial frequency alternating current from a supply 34' through the respective halves of an impedance or choke coil |35' and resistors 36, Si. Additional and similar restors 31 and 31 are connected between leads et and liand these resisters cooperate with condensers t3 and Sii' included in leads 33 and 33' extending from the plates of tubes 26, 2t' for supplying time derivative voltages to the grids oi' tubes lit and ilo', the said resistors completing the circuit for currents resulting from such voltages. A condenser il is connected between leads 38 and lili', and condensers lli. and d2' are also connected in series across these leads.- Condenser iii serves to smooth out voltage ripples. Condensers d2 and d2 serve to vary the voltage ratio between the A. C, and D. signals. If desired, condensers lli. and dii may be omitted.

Tubes il@ and lill are shown as having their `plates supplied from a transformer t3 fed from the A. C. supply 313', current from transformer Il to the plates of these tubes passing through relay coils Il and u'. Relay coils Il and Il' serve to actuate armatures 45 and 45 of switch blades 49 'and 49 controlling the supply of current from a battery or other source 4i to the armature of motor l1, having a constantly excited iield I8. Springs 24' normally hold switch blades Il and 49' in engagement with stationary contacts 5252.

In operation, as long as the craft proceeds on a straight course, the condenser plate I1 will remain in its central position equally pverlapplng condenser plates I8 and It. With condenser plate I1 in its central position, as shown in the drawings, .the voltage outputs of .tunable circuits 3|, 32 and 3|', 32 are equal, so that the oppos- 'ing outputs of tubes 2B and 28' fed through leads 38 and 38' to tubes 40 and 4G cause these latter tubes to draw equal currentsl through relay coils M and H', thereby causing the switchvblades 49 and 49 .to remain in engagement with contacts 52 and 52' so that motor 41 remains stationary.

As soon as the craft star-ts to turn. however, the gyroscope will precess, causing plate to move from its central position so as to overlap one of .the plates I8 or I8' more than the other,

' thereby increasing .the capacity between these plates.` Should the craft turn toward the left in Fig. 3, for example, the gyroscope will precess an amount depending on -the rate of turn of the craft, causing condenser plate il to move toward the lef-t so as lto overlie condenser plate il more than condenser plate i8', with the result that the output voltage of the tunable circuit 3|, 32 is considerably increased, whereas that of tunable circuit 3|', 32' is correspondingly decreased, with the result that unequal currents are drawn by tubes 28 and 26 through the two halves of choke coil 35. In this case. tube 2l draws a larger current than tube 26'. Thus, differentialaiternatlng E. M. F.s are applied to leeds 38 and 38 from supply 34' and pass through condensers 39 and 39 to the grids of tub Il and all', these E. M. F.s corresponding to the amount of precession of the-gyroscope,i. e., the

. relative displacement of plate I1 with respect to its central position. An unbalanced voltage surge or D. C. component ilows in choke coll |35 and in the resistors 36 and 36. the magnitude of which depends on the amount of procession of the gyroscope, and hence upon the rapidity of the turn. This surge component in choke coil |35' causes a voltage drop to appear across this coil as well as across resistors 3B and I8', the total voltage drop between leads 3B and Il' de- .pending as to phase upon .the direction of the turn and its magnitude being dependent upon the rate thereof.

li' this D. C. component varies, a voltage is induced across the choke coil |35', which induced voltage is in phase with the time rate of change of displacement of the condenser plate il from its central position,l that is, this voltage is. in phase with the time rate of change of the rate of turning, i. e., angular acceleration of the craft due to turn. During the turn two D. C. voltages appear across the leads 33 and d8', one proportional to and in yphase with 'the velocity of the turn, andthe other proportional to and in phase with the relative acceleration thereof. The combination of these two voltages is applied to condensers 3d and 39 and if `these two voltages are changing, the time rate of change thereof will be applied to the grids oi tubes llt and Ml.

time derivative rings shall be interpreted If desired, condensers I9 and il may be omitted.

Under the assumption that the turn is to the. left, causing the capacity between plates I1 and I8 to increase, the voltage applied to the grids of tube 40 will be in excess of that applied to tube 40', .with the'result that thecurrent through tube 40 increases while that through ltube '40' decreases and relay blade 49 is' actuated to engage stationary contact 50 while blade '49! engages contact l2', thereby causing the motor 4l to operate in one direction to effect a turning of platform l and Ithe gyroscope l to erase the turn, whereby this gyroscope is retained fixed in space, lthe indications of the scale 24 with respect to ypointer 54 carried by frame Il serving to indicate the amount of turn, the rate at which the card 24 turns with respect to pointer 54 giving indication of .the rate of turn. a

should' the craft turn .to the right, [the 'action is similar with the exception that the tunable circuit Il', 32' will have a larger voltage output, causing motor 4l to operate in .the reverse direction to maintain the gyroscope stationary in space, as is desired.

Thus, iby observing the card 24 .with respect to pointer I4, the aircraft operator is enabled; not only to know the total amount of turn for deviation of the craft from course, but also is enabled to know the rate of such deviation and can consequently readily correct for the turn to the desired extent, the card 24`serving as a fixed object, the same as any visible object yon the ground would serve in such case. Owing to the use of tentials, i. e., rate control in the control circuit of motor 4l, the system is rendered very sensitive and accurately indicates amount of turn` of the craft.

Since the device of this invention has no geographical direction, it is similar to the directional gyroscope in that it will preserve av heading which has been set up.

Although the device is shown in the drawings as operating in azimuth only, it is to be understood that the same may be made to operate about any axis, or a number of axes, if the same isdesired, by employing a number vof gyroscopes and follow-up motors for stabilizing the respective platforms of the gyroscopes used. It is also obvious that the type of motor 4l employed and its control from the tubes 40 and 4B may be varied within wide limits. Thus, if desired, ther current from tubes 40 and 40' may be fed directlyl into the armature of motor 51 in opposite directions as shown in Fig. 2 of Patent No. 2,126,910 of F. L. Moseley, or a repulsion motor may be used, if desired, as shown in this patent.

As many changes could be made in the above construction and many apparently 'widely different embodiments of this invention could be made -without departing from the scope thereof, it is intended' that all matter contained in the above description or shown in the accompanying drawas illustrative and not .in a limiting sense.

:What is claimed is:

1. In an instrument of the character described for showing the direction and amount of deviation of a craft from course, a` rotatable support,

. a constrained gyroscope mounted thereon for precession throughan angle dependent upon the rate of' turn of. the craft, motivemeans to'turn said support,- control means including a pick-oil from said gyroscope so constructed and arranged as to cause" said motive means to be driven in a direction and at a'rate dependent upon the direc-V tion and, at least in part, upon the extent of precession of said gyroscope i so as to counteract said precession, and a course indicator rotatable with said'support.

2. In an instrument of the character described. a constrained gyroscope with horizontal spin axis and mounted for procession around an axis per'- pendlcular thereto, means for rotatably supporting said gyroscope about a third axis, motive means for rotating said 'supporting means to counteract said procession, and control means for said motive means including a pick-olf from said gyroscope operated by and' upon precession of said gyroscope due to turning about said third axis, to-cause said motive means to turn said supporting means in the reverse direction.. to thereby maintain the suDPQljiing-means angularly stationary about its axis of rotation.

. .3. A direction indicator for aircraft showing the direction and amount of deviation from course, comprising 'a .constrained gyroscope mounted for precessi'on through an angie dependent on the rate of turn of the craft, a compass card indicator, an electric motor for actuating said indicato and control means comprising tunable circuits including a differential capacity Ipick-off from said gyroscope and thermioriic tube means fed from said tunable circuits for causing said motor and said indicator to lbe driven inia direction and at a rate respectively depende `t upon the direction and' a function of the angular precessional displacement of said gyroscope.

, mounted for precession through an angle dependenton the rate of turn of the craft, a compass card indicator, an electric motor for actuating said indicator, and control means comprising tunable circuits including a differential capacity pick-oi from said' gyroscope, a high frequency .source for energizing said tunable circuits, thermionic means fed from said circuits and `serving to amplify and rectify the alternating potential output thereof, and relays controlled from the output of said thermionic means for controlling the operation of said motor, whereby said indicator isdrivenin a direction and at a rate respectively dependent upon the direction and a function of the angular precessional displacement of said gyroscope.

5. A direction indicator for aircraft showing the direction and amount of deviation from course, comprising a constrained gyroscope mounted for' precession through an angle dey pendent on the rate of turn of the craft, a compass card indicatorncontrol means comprising tunable circuits including a differential capacity pick-off from said gyroscope, a high frequency source for energizing said tunable circuits, thermionic -means fed from said circuits and serving to amplify and rectify the alternating potential output thereof, said thermionic means haying impedance in its output circuit for producing surge potentials, and motive means controlled from-said thermionic means and said impedance for actuating said compass card indicator.

6. In an instrument for integrating turning said gyroscope, a support for said gyroscope turnable about an axis at fhl; axis of. said gyroscope, -an said support, a motor for t angles to the rotating dicator carried by said' support t0 suppress said precession, a frictionless electrical pick-oil' operated by and upon precession of said| gyroscope, and a control circuit for said motor connected to said pick-oft', said control circuit controlling said motor in response to the precession of said gyroscope and a time derivative thereof.

7. In a gyroscopic instrument of the rate of turn type for showing the direction and amount of deviation of a craft from its course, a constrained gyroscope mounted for precession about an axis normal to the axis of deviation, a turntable support for said gyroscope, motive means for turning said support to stop said procession, control means including a pick-off operated by and upon precession of said gyroscope so con-I structed and arranged as tocause said motive means to be driven in a direction to stop said precession and at a rate dependent upon the amount and direction of said precession and a time derivative thereof, and a course indicator actuated by said motive means.

8. As a means for controlling the position of a member in response to both its angular rateand anguiaracceleration comprising a two-degree of freedom rate of turn gyroscope mounted on said member, a pick-off thereon the position of which is altered by procession of said gyrcscope responsive to said angular rate, a servo motor controlled by the signal from said pick-off for moving said member, and means for modifying said signal by a time derivative of the signal.

9. As a means for controlling the position of a member in response to both its angular rate and angular acceleration comprising a two-degree-offreedom, constrained rate of turn gyroscope mounted on said member, a non-contacting eiectrical pick-off on saidf gyroscope giving a signal proportional to the extent of procession of said gyroscope corresponding to theangular rate of said mem-ber, an amplifying circuit for said signal including means for deriving a time derivative thereof, and a servo motor for moving said member controlled by the output of said circuit.

JOSEPH LYMAN. 

